The constant modulus algorithm (CMA) is an unsupervised adaptive filter that achieves interference cancellation in multiple input multiple output (MIMO) communication systems. This paper studies the performance weighted of CMA algorithm based on the measuring data of MIMO channel. By analyzing both the asymptotic mean square error (MSE) and bit error rate (BER) of the efficient weighted channel of the CMA algorithm, also simulation and measurement results are compared with a different of the antenna orientation. Experimental results demonstrate that the CMA algorithm can reduce the MSE and BER at 2.45 GHz for wireless RFID system very well.